System and method for manufacturing positive electrode for secondary battery

Abstract

A system for manufacturing a positive electrode for a secondary battery includes an unwinder wound with a positive electrode base material, a first coating unit for coating an insulating material at predetermined positions about widthwise edges of the base material with respect to a transfer direction of the base material supplied from the unwinder, a first drying furnace for drying the insulating material by heating the base material coated with the insulating material, a second coating unit for coating a positive electrode slurry on the base material supplied from the first drying furnace in a region between the insulating material formed at both sides of the base material, and a second drying furnace for heating and drying the base material coated with the insulating material and the positive electrode slurry.

What is claimed is: 
     
       1. A system for manufacturing a positive electrode for a secondary battery, the system comprising:
 an unwinder wound with a positive electrode base material; 
 a first coating unit configured to coat an insulating material at predetermined positions about widthwise edges of the positive electrode base material with respect to a transfer direction of the positive electrode base material supplied from the unwinder; 
 a first drying furnace configured to dry the insulating material by heating the positive electrode base material coated with the insulating material; 
 a second coating unit configured to coat a positive electrode slurry on the positive electrode base material supplied from the first drying furnace in a region between the insulating material formed at both sides of the predetermined positions about widthwise edges of the positive electrode base material; and 
 a second drying furnace configured to heat and dry the positive electrode base material coated with the insulating material and the positive electrode slurry. 
 
     
     
       2. The system of  claim 1 , wherein the predetermined positions on the positive electrode base material to be coated with the insulating material are positioned between an electrode portion formed at a central portion of the positive electrode and lead portions formed at both ends of the positive electrode. 
     
     
       3. The system of  claim 1 , wherein the second coating unit comprises a slot die coater configured to coat the positive electrode slurry on the positive electrode base material, wherein the positive electrode slurry is configured to be supplied through an internal passage and coated through a nozzle. 
     
     
       4. The system of  claim 3 , wherein the slot die coater is configured to set a coating thickness of the positive electrode slurry by adjusting a gap with respect to the positive electrode base material and to form a positive electrode portion by applying the positive electrode slurry between the insulating material formed on both sides of the positive electrode base material. 
     
     
       5. The system of  claim 1 , further comprising a re-winder configured to recollect a positive electrode film formed by coating and drying the insulating material and the positive electrode slurry on the positive electrode base material by winding the positive electrode film into a roll. 
     
     
       6. The system of  claim 1 , wherein the positive electrode base material comprises an aluminum foil. 
     
     
       7. A system for manufacturing a positive electrode for a secondary battery, the system comprising:
 an unwinder wound with a positive electrode base material; 
 a first coating unit configured to coat an insulating material at predetermined positions about widthwise edges of the positive electrode base material with respect to a transfer direction of the positive electrode base material supplied from the unwinder; 
 a first drying furnace configured to dry the insulating material by heating the positive electrode base material coated with the insulating material; 
 a second coating unit configured to coat a positive electrode slurry on the positive electrode base material supplied from the first drying furnace in a region between the insulating material formed at both sides of the predetermined positions about widthwise edges of the positive electrode base material; and 
 a second drying furnace configured to heat and dry the positive electrode base material coated with the insulating material and the positive electrode slurry; 
 wherein the first coating unit comprises:
 a pan configured to store the insulating material in a liquid state; and 
 a gravure roll rotatably disposed within the pan through a rotation shaft, and having coating surfaces formed on an exterior circumference of the gravure roll, the coating surfaces configured to transfer the insulating material to the positive electrode base material to form an insulating portion. 
 
 
     
     
       8. The system of  claim 7 , wherein the gravure roll is installed to be immersed in the insulating material within the pan and is configured to form the coating surfaces at each exterior circumference at both sides of the gravure roll. 
     
     
       9. The system of  claim 8 , wherein the coating surfaces are symmetrically formed with respect to a center of the gravure roll through intaglio molding. 
     
     
       10. The system of  claim 7 , further comprising:
 a storage tank configured to supply the insulating material to the pan; 
 a mixer disposed in the storage tank and configured to mix the insulating material; 
 a supply hose connecting the storage tank and the pan; and 
 an adjustment valve installed on the supply hose. 
 
     
     
       11. The system of  claim 7 , wherein the predetermined positions on the positive electrode base material to be coated with the insulating material are positioned between an electrode portion formed at a central portion of the positive electrode and lead portions formed at both ends of the positive electrode. 
     
     
       12. The system of  claim 7 , wherein the second coating unit comprises a slot die coater configured to coat the positive electrode slurry on the positive electrode base material, wherein the positive electrode slurry is configured to be supplied through an internal passage and coated through a nozzle. 
     
     
       13. The system of  claim 12 , wherein the slot die coater is configured to set a coating thickness of the positive electrode slurry by adjusting a gap with respect to the positive electrode base material and to form a positive electrode portion by applying the positive electrode slurry between the insulating material formed on both sides of the positive electrode base material. 
     
     
       14. The system of  claim 7 , further comprising a re-winder configured to recollect a positive electrode film formed by coating and drying the insulating material and the positive electrode slurry on the positive electrode base material by winding the positive electrode film into a roll. 
     
     
       15. The system of  claim 7 , wherein the positive electrode base material comprises an aluminum foil. 
     
     
       16. A method of using a system to manufacture a positive electrode for a secondary battery, wherein the system comprises an unwinder wound with a positive electrode base material, a first coating unit, a plurality of rollers between the unwinder and the first coating unit, a first drying furnace, a second coating unit, and a second drying furnace, the method comprising:
 unwinding the positive electrode base material wound on the unwinder and transferring the positive electrode base material to the first coating unit through the plurality of rollers; 
 using the first coating unit to coat an insulating material at predetermined positions about widthwise edges of the positive electrode base material with respect to a transfer direction of the positive electrode base material supplied from the unwinder; 
 using the first drying furnace to dry the insulating material by heating the positive electrode base material coated with the insulating material; 
 after using the first drying furnace to dry the insulating material, using the second coating unit to coat a positive electrode slurry on the positive electrode base material supplied from the first drying furnace in a region between the insulating material formed at both sides of the predetermined positions about widthwise edges of the positive electrode base material; and 
 using the second drying furnace to heat and dry the positive electrode base material coated with the insulating material and the positive electrode slurry. 
 
     
     
       17. The method of  claim 16 , wherein using the first coating unit to coat an insulating material at predetermined positions comprises:
 rotating a gravure roll immersed in the insulating material accommodated in a pan so as to form the insulating material on coating surfaces formed on an exterior circumference of the gravure roll; and 
 coating the insulating material at the predetermined positions of the positive electrode base material corresponding to the coating surfaces by the rotation of the gravure roll through a contact between the gravure roll and the positive electrode base material. 
 
     
     
       18. The method of  claim 17 , wherein the coating surfaces are symmetrically formed with respect to a center of the gravure roll through intaglio molding. 
     
     
       19. The method of  claim 16 , wherein using the second coating unit to coat a positive electrode slurry on the positive electrode base material comprises:
 adjusting a gap between the positive electrode base material and a slot die coater; and 
 supplying the positive electrode slurry to the positive electrode base material through an internal passage of the slot die coater so as to coat the positive electrode slurry on the positive electrode base material through a nozzle. 
 
     
     
       20. The method of  claim 16 , further comprising using a re-winder to recollect a positive electrode film formed by coating and drying the insulating material and the positive electrode slurry on the positive electrode base material by winding the positive electrode film into a roll.